/// <summary>
        ///  LINQ on database
        /// </summary>
        public static IQueryable <Aql> Query(this IArangoContext context, ArangoHandle handle)
        {
            var queryParser = new AqlParser(new ArangoLinq(context, handle));

            return(queryParser.CreateQueryable <Aql>());
        }
        /// <summary>
        ///  LINQ in sub-expression
        /// </summary>
        public static IQueryable <T> Query <T>(this IArangoContext context)
        {
            var queryParser = new AqlParser(new ArangoLinq(context, null));

            return(queryParser.CreateQueryable <T>());
        }